Objective To understand the distribution and antimicrobial susceptibility of clinically isolated bacteria from department of rheumatology and immunology in China in 2021. Methods According to China Antimicrobial Resistance Surveillance System (CARSS) program, information of clinically isolated bacteria from department of rheumatology and immunology reported by all CARSS member hospitals in 2021 were statistically analyzed. Antimicrobial susceptibility testing results were interpreted according to the standards from Clinical and Laboratory Stan-dards Institute (CLSI). Results In 2021, 28 863 strains of non-repetitive bacteria were isolated from patients in the department rheumatology and immunology, with Gram-negative bacteria and Gram-positive bacteria accounting for 72.0% (n=20 784) and 28.0% (n=8 079), respectively. The top five detected bacterial strains were Escherichia coli (n=9 825, 34.0%), Klebsiella pneumoniae (n=3 222, 11.2%), Staphylococcus aureus (n=3 002, 10.4%), Pseudomonas aeruginosa (n=1 793, 6.2%) and Enterococcus faecalis (n=866, 3.0%). The specimens were mainly from urine (n=13 496, 46.8%), sputum (n=7 597, 26.3%), blood (n=2 402, 8.3%) and pus (n=1 243, 4.3%). Isolation rates of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coa-ulase negative Staphylococcus (MRCNS) were 22.8% and 67.2%, respectively. The resistance rate of MRCNS to linezolid was 0.1%, and no strains were found to be resistant to vancomycin and teicoplanin. Resistance rates of Enterococcus faecalis and Enterococcus faecium to vancomycin and linezolid were 0.2%-4.0%. Resistance rate of Streptococcus pneumoniae isolated from non-cerebrospinal fluid specimens to penicillin was 2.8%. Resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannii to impenem were 9.6% and 20.2%, respectively. Resis-tance rates of Escherichia coli to cefotaxime and imipenem were 41.0% and 0.9%, respectively. Resistance rates of Klebsiella pneumoniae to cefotaxime and imipenem were 18.2% and 4.5%, respectively. Resistance rate of Haemophilus influenzae to ampicillin was 69.4%. Conclusion Clinically isolated bacteria from patients in department of rheumatology and immunology mainly come from urine specimens, and antimicrobial resistance of bacteria still remains at a high level.